Next we turn to the problem of demixing. We begin with an analysis of a challenging voltage imaging dataset. Voltage imaging (VI) data presents a few important challenges compared to calcium imaging (CI) data: currently-available VI data typically has much lower SNR and displays much stronger bleaching effects than CI data. The dataset we focus on here has another challenging feature: the preparation was driven with time-varying full-field optogenetic stimulation, resulting in highly correlated subthreshold activity in the visible cells, which are highly overlapping spatially. In preliminary analyses of this data we applied variants of CNMF-E [1]} but did not obtain good results (data not shown), due to the strong bleaching and optogenetic stimulation-induced correlations present in this data.
